Various types of automated poultry eviscerating machines have been developed which receive birds carried in a legs-up attitude on an overhead conveyor and which insert an eviscerating tool into the previously opened cavity of the bird so as to extract the viscera from the bird. Some of the prior art machines are represented by U.S. Pat. Nos. 3,653,093, 3,806,988, 3,979,793, and 3,902,221. Some of the prior art eviscerator machines require a substantial amount of rather complex hardware to cause the working elements of the system to function. For example, various latches, springs, cams, bearings and other elements have been used to cause the eviscerator tool to reciprocate and/or tilt during its viscera removal functions. These various parts are expensive to manufacture and assemble, are subject to wear and deterioration, and are subject to malfunction. The exposure of the multiple number of mechanical parts in the eviscerating process subjects the parts to an accumulation of filth which must be washed or otherwise removed from the equipment in order to comply with government sanitation requirements.
It is desirable that poultry eviscerating equipment not only function effectively to remove the viscera of the fowl with a minimum of damage to the carcass and the viscera, but also that the eviscerating function take place with a minimum of contamination from the birds to the equipment and from the equipment back to subsequent ones of the birds. One poultry eviscerator that has been developed comprises an outer work cylinder assembly which is rotated on its vertical axis by the overhead conveyor system and rotates concentrically about a stationary inner cam drum assembly. Each bird carried by the overhead conveyor is received at a work station on the outer work cylinder and is moved with the cylinder through approximately 180.degree.. The work cylinder includes a plurality of bird guide elements protruding outwardly therefrom to guide the birds to and maintain the birds in predetermined work stations about the work cylinder during the movement of each bird about the work cylinder, and each bird is clamped against the cylindrical work surface with its back in abutment with the work surface. An eviscerator tool is thrust downwardly into the cavity of the bird while the bird is held in place against the work cylinder with the tool moving first along the breast side of the cavity and then, after reaching the bottom of the cavity, the tool is moved upwardly along the back side of the cavity. Some of the viscera passes through the loop of the tool and the viscera tends to be collected in the tool and viscera is pulled by the tool out of the cavity as the tool is moved upwardly, and as the tool withdraws from the cavity of the bird the viscera is laid over the exterior tail portion of the bird where it can be visually inspected and removed from the bird. The birds then continue to be moved by the conveyor away from the eviscerator machine.
The work cylinder functions as a moving support against which each bird can be clamped during the eviscerating step. Projections mounted on the external surface of the work cylinder guide the birds toward and help to maintain the birds in the desired location and attitude at the work cylinder while the eviscerator tools move in the cavities of the birds. The work cylinder also functions to shield the other components from contamination by the birds and the work cylinder is easy to clean.
One of the problems experienced with eviscerator machines that include elements for holding birds in position during the eviscerating procedure is that is is desirable to relocate the bird holding elements when birds of a different size are to be eviscerated. For example, if the processing line has been set to handle large chickens or turkeys and the line is later required to handle smaller chickens or guineas, the guide elements become less effective in guiding and maintaining the birds in the desired work stations during the evisceration procedure. This might result in movement of the birds at the work stations and in the eviscerator tool reaching too far into the cavity of the bird and damaging the bird or in not reaching far enough into the cavity of the bird and not retrieving the lungs or other organs from the bird.
One prior solution to moving bird holding elements has been to disconnect the work cylinder from the rest of the eviscerator, raise or lower the work cylinder and reconnect it to the eviscerator. This requires the eviscerator to be taken off the processing line or stopping the processing line for a substantial length of time.